How to remove the "Show Passwords" button in Firefox

Firefox has a really annoying feature where anyone using your computer can open firefox, open the preferences form, click "Saved Passwords" on the "Security" tab then click the "Show Passwords" button to reveal all of your saved passwords.

These passwords could be for your e-mail account or even your Paypal account. Any chump that got on your computer could do this, unless, of course, you use a master password. But this solution is annoying. So here's how to remove that horrible "Show Passwords" button:

Open a text editor and paste the following text into a new file:

button#togglePasswords { display: none !important }

Save this text file as userChrome.css in the folder called chrome in your Firefox profile folder.